General Packet Radio Services (GPRS) networks are routinely used to provide packet data services to mobile stations, or wireless units. The mobile station communicates over a wireless interface with a base station, and the mobile station sends and receives data over the wireless interface in the form of data packets. The GPRS network also usually includes support nodes, which facilitate communication between the mobile stations and other elements in the GPRS network. The support nodes also facilitate communication with external networks such as the Internet.
Conventional GPRS systems typically use a Frame Relay network as the backbone network in the system. The Frame Relay backbone network transports information between the different elements in the GPRS system. A corporation, organization, or other enterprise may wish to create a private network for internal use by its own personnel, and the private network communicates with the public GPRS system. One approach to providing a private GPRS network involves adding discrimination capabilities to an element in the public GPRS system, such as in the Home Location Register (HLR). The HLR determines whether a mobile station is in the public GPRS system or a private GPRS network, and the HLR processes data packets transported to and from the mobile station depending on the location of the mobile station.
One problem with this approach is the lack of Frame Relay networks in many enterprises. The public GPRS system typically uses a Frame Relay network as a backbone network. Enterprises often use an internal packet network, such as an Internet Protocol network, to provide computing and data services to its personnel, but enterprises may not use internal Frame Relay networks. The lack of an internal Frame Relay network in an enterprise makes it difficult for the enterprise to establish a private GPRS network.
Another problem with this approach is that it is difficult to add functionality to existing HLRs. Adding functionality to existing HLRs typically requires the addition of hardware, software, and/or firmware to the design of the HLRs. This increases the complexity of the HLR, which also increases the cost of the HLR. Also, modifying the HLR to provide custom features to mobile stations in all private GPRS networks may prevent other customized functions from being deployed and used in specific private GPRS networks.
In addition, adding discrimination functionality to the HLR typically involves the implementation of proprietary functions in the HLRs. Each HLR manufacturer typically implements the discrimination function using proprietary methods and technology. As a result, it is difficult to add HLRs to a public GPRS system. The HLRs of one manufacturer may not work properly with HLRs from other manufacturers because of the proprietary nature of the discrimination functions.